<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>

  h1{
  color:red;
  }
  #id1,#id2,#id3{
    color: green;
  }
.c{
  color:cyan;
}
h1,#id1,.d{
    color: deeppink;
}
input[type='text']{
    color: red;
}
*{
    border: 1px solid red;
}
  </style>
</head>
<body>
<h1>哦豁</h1>

<h1 id="id1">哦豁</h1>
<h2 id="id2">哇塞</h2>

<h2 class="d">哇塞</h2>
<p class="c">弄啥哩</p>
<input type="text">
<input type="password">
</body>
</html>